ach pair of main
engines. Each section is thus separated from those adjoining, so that
any escape of steam in one section can be localized and, by means of
the quick-closing valves, the piping for the corresponding pair of
main engines can be disconnected from the rest of the power house.

[Illustration: VIEW FROM TOP OF CHIMNEY SHOWING WATER FRONTAGE--POWER
HOUSE]

All cast iron used in the fittings is called air-furnace iron, which
is a semi-steel and tougher than ordinary iron. All line and bent pipe
is of wrought iron, and the flanges are loose and made of wrought
steel. The shell of the pipe is bent over the face of the flange. All
the joints in the main steam line, above 2-1/2 inches in size, are
ground joints, metal to metal, no gaskets being used.

Unlike the flanges ordinarily used in this country, special extra
strong proportions have been adopted, and it may be said that all
flanges and bolts used are 50 per cent. heavier than the so-called
extra heavy proportions used in this country.

[Sidenote: _Water Piping_]

The feed water will enter the building at three points, the largest
water service being 12 inches in diameter, which enters the structure
at its southeast corner. The water first passes through fish traps
and thence through meters, and from them to the main reservoir tanks,
arranged along the center of the boiler house basement. The water is
allowed to flow into each tank by means of an automatic float valve.
The water will be partly heated in these reservoir tanks by means of
hot water discharged from high-pressure steam traps. In this way the
heat contained in the drainage from the high-pressure steam is, for
the most part, returned to the boilers. From the reservoir tanks the
water is conducted to the feed-water pumps, by which it is discharged
through feed-water heaters where it is further heated by the exhaust
steam from the condensing and feed-water pumps. From the feed-water
heaters the water will be carried direct to the boilers; or through
the economizer system to be further heated by the waste gases from the
boilers.

[Illustration: PORTION OF MAIN STEAM PIPING IN PIPE AREA]

Like the steam-pipe system, the feed-water piping is laid out on the
sectional plan, the piping for the several sections being identical,
except for the connections from the street service to the reservoir
tanks. The feed-water piping is constructed wholly of cast iron,
except the piping above the floor line